An Animal Core has been included in this competitive renewal in response to the recommendation of our External Scientific Review Board. We agree with their observation that a centralized Animal Core will be critical for standardization of animal treatments, optimal utilization of animals and facilities, and facilitation of project integration. These overall objectives will be realized by achieving the following: i. implementation of standardized animal treatment procedures to optimize integration of findings between the projects and to ensure confidence in data comparisons between the projects. ii. enhance efficiency and convenience of animal experiments. minimize unnecessary delays and assure availability of treated animals as required for studies, iv. reduce costs by efficient standard bulk and volume purchasing for both animals and related supplies. These overall goals will be achieved through weekly meetings between the personnel of the Animal Core, Drs. Gibb and Hanson (director and co-director of the Administrative Core), and the Project leaders. During these meetings, progress during the previous week will be evaluated and future experiments will be identified and planned. All animal housing and procedures will be performed in a recently renovated and state-of-theart vivarium facility dedicated to research with the psychostimulants such as METH and conveniently located to the laboratories of the participants in this Program Project. The Animal Core will be directed by Dr. Mario Alburges who was involved in the previous grant and has extensive experience in animal research and the study of METH. He will be assisted by a full and 2/3-time technicians.